1. Technical Field
The present invention relates to a technology for configuring high-speed optical transmission and flexible network by using a WDM (wavelength division multiplexer) in an optical access system, and more particularly, to a WDM-PON (passive optical network) as one of the technologies for configuring an optical access system.
2. Background Art
Recently, a WDM-PON for configuring high-speed optical transmission and flexible network by using a WDM in an optical access system have been researched and developed in the world (for example, refer to A. Banerjee, et al., “Wavelength-division-multiplexed passive optical network (WDM-PON) technologies for broadband access: a review”, Journal of Optical Networking, Vol. 4, No. 11, pp. 737-758, November 2005 and Japanese Patent Application Laid-Open Publication No. 2004-222304). In the WDM-PON, a PON topology where an optical fiber is branched by an optical splitter is used, and each subscriber premises apparatus (hereinafter, referred to as optical network unit) is allocated with a wavelength for transmission, so that high-speed optical transmission or long-distance optical transmission between a central office apparatus (hereinafter, referred to as optical line terminal) and each optical network unit can be implemented.
As the high-speed optical transmission technology, there are developed various technologies of optical repeating systems (for example, refer to M. N. Islam, “Raman Amplifiers for Telecommunications”, IEEE Journal of Selected Topics in Quantum Electronics, Vol. 8, No. 3, pp. 548-559, May/June 2002). Therefore, the high-speed optical transmission technologies of the optical repeating system can be applied to the WDM-PON.